Electrical pulsating drive



April 20, 1948- M. N. YARDENY ET AL 2,440,228

ELECTRICAL PULSATING DRIVE Filed Oct. 15, 1945 45 48 FlGi Mal /4 M25:EDEN) C/v A m 5 Pm/VDLE IN V ENTO R 5 ATTOR 'ior Patented Apr. 20, 1948ELECTRICAL PULSATIN G DRIVE Michel N. Yardeny, New York,

and Charles Prindle, Long Island City, N. Y.; said Prindle assignor tosaid Yardeny ApplicationOctober 15, 1945, Serial No. 622,462

8 Claims.

This invention relates to control devices, and has particular referenceto control devices for supplying energy to electrical devices such asmtors at a desired rate.

The main object of this invention is to provide acontrol apparatus ofthe foregoing general type adapted to be manually operated forcontrolling the how of electric current to a motor or similar device insuch a manner that the energy is supplied to the deviceby impulses sothat the average amount of power delivered per unit of time may bevaried by varying the number and/or duration of impulses per unit oftime, thereby controlling,

instance, the speed of the motor.

An allied object of this invention is to provide means to prevent theflow of current to the motor when the control device is not operated.

A further object of the invention is to provide means to establish acontinuous flow of energy when the control device is manipulated at asumoiently rapid rate.

Still a further object of this invention is to provide supplementarymeans for connecting the motor directly to a source of current.

The foregoing and other objects, features and advantages of thisinvention are more fully described ln the accompanying specification anddrawing, in which:

Fig. 1 is a diagrammatic planview showing a now preferred embodiment ofa control device according to the invention and the electricalconnections thereof; and

Fig. 2 is a sectional elevational view of the control device along line2-2 of Fig. l.

The control device according to this invention comprises a star ortoothed Wheel I having camshaped teeth 2, and threaded on a stem of aninsulation knob 3 to which it is secured by a lock nut 4. The knob 3 ismounted for rotation on a vertical shaft 8 extending from an insulationbase 9, and may be knurled at the periphery to faci1it'ate its manualoperation.

The teeth 2 engage a lug or tooth in on a lever II pivotally mounted atone end on a pin i2 extending from the base 9. A spring I4 urges lever Htowards the star wheel I. The other end of lever i I is connected by aspring I5 to the contact arm I5 pivotally supported on a fixed pin I1and positioned to engage one or the other of contacts 2012i mounted onbase 9.

The knob 3' further carries a contact arm 22 frictionally retained inits place by a spring washer 23 pressing the contact arm against a hubofstar wheel I. The end of the arm 22 moves between stationary resilientcontacts 25, 26 supported by posts 21, 28 extending from base 9. Thecontacts 25, 25 are connected by leads 30, 3! to the ends reversingfield windings 32, 33 respectively of a, motor 34. The other ends of theWindings are joined together and connected to one terminal of the motorarmature 38. The other armature terminal is ccnnected by a lead 3'! toan armature 38 of a relay 48. The relay armature 38 normally engages acontact 4! connected by a lead 52 through a switch 44 to a terminal 25of a source of current. One terminal of the relay 40 is connected by alead 46 through a switch il to the other terminal 48 of the source ofcurrent, the other relay terminal being connected by a lead is to thecontact arm iii. The contacts 253, 2? are connected by leads 5%, 5i tothe supply Wire 42. The contact arm 22 is connected by a lead (-3 to thesupply wire 46.

As will be seen on the drawing, the contact arm I6 normally engages oneor the other of the contacts 20, 2i, thus energizing the relay 4athrough leads 5I and 49, whereby the motor circuit is interrupted. Forenergizing the motor, the knob 3 is manually rotated, causing thesuccessive teeth 2 to engage the tooth Ill thereby reciprocating thelever II about its pivot I2. It

may be noted that the spring I5 urges the contact arm I5 into theengagement with one or the other of the contacts 25, 26, depending onthe position of the lever II, relative to pivot ll of arm I 6. When thelever II is moved from one of its extreme positions as, for instance,from the position shown in full lines in Fig. 1 into the position shownin dashed lines, spring IE will continue to press arm I6 against contact2i until the end of the lever passes to the other side of the pivot I1,whereupon the direction of the pull of spring I5 will be changed,causing the arm It to snap from its extreme right position to itsextreme left position, in which it engages the contact 20. In either ofthese positions relay 46 will be energized, the current passing fromsupply wire 42 through lead 5|, contact 20, or lead 59 and contact 2i;contact arm I6, lead 49, relay coil 40 to supply lead 46. The energizedrelay will attract the armature 38, breaking the motor circuit atcontact 4!. thereby deenergizing the motor. The relay will bedeenergized only during the short interval of time when the contact armI6 snaps from one extreme position into the other, i. e. when it isdisengaged from either of the contacts 20, 2 I.

The motor will be energized for rotation in one Or the other direction,depending on the direction of rotation of the knob 3. Assuming that theknob is turned to the right, the contact arm 22 will be pressedagainstthe resilient contact 25, and the motor circuit will be closedwhile relay 4!] is deenergized as follows: from the supply wire 46 bythe lead 53, arm 22, contact 25, lead 30, winding 33, motor armature 33,lead 31, relay armature 38, contact 4!, to the other sup ply lead 42.The motor will continue receiving impulses of current while knob 3 isrotated, the relay being alternately energized and deenergized. With theincrease in the rotational speed of the knob, however, the relay willremain deenergized for a longer period after each energy impulse so thatthe motor will receive longer energy impulses, thereby increasing itsspeed. When the speed of the knob exceeds a certain limit, however, therelay will, due to its time factor or lag, cease to attract its armatureand the motor will remain continuously energized.

The movable parts of the device can be so proportioned that at asufficiently high speed of the manual rotation of the knob 3, the numberof the current interruptions will be so large that the relay 40 will notbe able to follow the current impulses, so that the armature 38 willremain in engagement with the contact 4|, continuously energizing themotor. The latter will then receive a continuous flow of energy and willoperate at a high speed for advancing a load to its final position. Whenthe final position is approached, however, the rotation of the knob 3 isslowed down, causing the motor to receive a pulsating current withcorresponding reduction in the speed of the motor. By graduallyretarding the speed of the motor it becomes possible to stop the motorinstantly when the exact desired position of the load is reached.

An additional attachment is provided for closing the motor circuitindependently of the relay when it is desired to operate the motor atfull speed without corresponding rapid rotation of the knob 3. For thispurpose the knob 3 is made axially slidable on the shaft 8, beingretained within certain limits by a pin 56 passing through the stem ofthe knob and engaging a recess 51 in the shaft 8. A resilient contactspring 58 normally holds the knob 3 in a raised position as shown inFig. 2 separated from a contact 60.

In the event that it is desired to close the motor circuit independentlyof relay All, knob 3 is depressed, thereby closing contacts 58 and 63,thereby establishing a motor circuit which may be traced from leadthrough leads 53, 6!, contacts Bil, 58, leads B2, 31, motor armature 36,one of the motor windings, say winding 33, lead 30, contact 25, contactarm 22, and lead 53.

While the invention has been described in detail with respect to acertain particular preferred example, it will be understood by thoseskilled in the art after understanding the invention, that variouschanges and further modifications may be made without departing from thespirit and scope of the invention and it is intended therefore in theappended claims to cover all such changes and modifications.

What is claimed as new and desired to be secured by Letters Patent is:

1. An electric control apparatus comprising contact means; a contact armmovably supported and adapted to engage the contact means; means toperiodically and alternately move the contact arm into and out ofengagement with the contact means; means to render the position of thecontact arm unstable between alternate positions; circuit meansincluding the contact means for supplying electric current to anelectrical device during the period of unstable arm positions andinterrupting the current during the period of stable arm positions; andmeans included in the circuit means to vary the period of current supplyrelative to the period of current interruption in response to avariation of the speed of the contact arm moving means.

2. An electric control apparatus comprising contact means; a contact armmovably supported and adapted to engage the contact means; means toeriodically and alternately move the contact arm into and out ofengagement with the contact means; means to render the position of thecontact arm unstable between alternate positions; circuit meansincluding the contact means for supplying electric current to anelectrical device during the period of unstable arm positions andinterrupting the current during the period of stable arm positions; andmeans included in the circuit means to increase the period of our- Vrent supply relative to the period of current interruption in responseto an increase of the speed of the contact arm moving means.

3. An electric control apparatus comprising contact means; a contact armmovably supported and adapted to engage the contact means; means toperiodically and alternately move the contact arm into and out ofengagement with the contact means; means to render the position of thecontact arm unstable between alternate positions; relay means; circuitmeans including the contact means and the relay means for supplyingelectric current to an electrical device during the period of unstablearm positions and interrupting the current during the period of stablearm positions, said relay means having a lag selected to increase theperiod of current supply relative to the period of current interruptionin response to an increase of the speed of the contact arm moving means.

4. An electric control apparatus comprising a pair of contacts; acontact arm movably supported for engaging one or the other of thecontacts; means to periodically and alternately move the contact arminto engagement with the contacts; means to render the positions of thecontact arm between the contacts unstable; a relay for controlling anelectrical device; and circuit means including the contacts and therelay for supplying electric current to the electrical device during anunstable position of the contact arm and interrupting the current whenthe contact arm engages one of the contacts, said relay beingconstructed to have progressively increasing lag in its responses to aclosing of the relay circuit, thereby progressively increasing thelength of current impulses to the electrical device With an increase inthe frequency of the movement of the contact arm, until the currentbecomes continued above a certain speed,

5. An electric control apparatus comprising a pair of contacts; acontact arm movably supported for engaging one or the other of thecontacts; a rotary member for periodically and alternately move thecontact arm from one contact to the other; resilient means to urge thecontact arm into engagement with one or the other of the contacts and torender the positions of the contact arm unstable between the contacts;circuit means including the contacts for supplying electric current toan electrical device during the period of unstable arm positions andinterrupting the current during the period of stable arm positions; andmeans included in the circuit means to increase the period of currentsupply relative to the period of current interruption in response to anincrease of the speed of the rotary member.

6. An electric control apparatus comprising a pair of contacts; acontact arm movably supported. for engaging one or the other of thecontacts; a rotary member for periodically and alternately move thecontact arm from one contact to the other; resilient means to urge thecontact arm into engagement with one or the other of the contacts and torender the positions of the contact arm unstable between the contacts;relay means; circuit means including the contacts and the relay meansfor supplying electric current to a motor during the period of unstablearm positions and interrupting the current during the period of stablearm positions, said relay means having a lag selected to increase theperiod of current supply relative to the period of current interruptionin response to an increase of the speed of the rotary member.

7. An electric control apparatus comprising a pair of contacts; acontact arm movably supported for engaging one or the other of thecontacts; a lever pivotally supported at one end; a resilient memberconnecting the lever with the contact arm; a toothed rotary member; aspring urging the lever into engagement with the rotary member forurging the contact arm towards one contact or the other depending on theposition of the lever and to render the positions of the contact armunstable between the contacts; relay means; circuit means including thecontacts and the relay means for supplying electric current to a motorduring the period of unstable arm positions and interrupting the currentduring the period of stable arm positions, said relay means having atime factor selected to increase the period of current supply relativeto the period of current interruption in response to an increase of thespeed of the contact members.

8. An electric control apparatus comprising a pair of contacts; acontact arm movably supported for engaging one or the other of thecontacts; a lever Divotally supported at one end; a resilient memberconnecting the lever with the contact arm; a toothed rotary membermounted for axial displacement; a spring urging the contact arm towardsone or the other of the contacts depending on the position of the lever,and to render the intermediate positions of the contact arm unstable; areversible electric motor; circuit means including the contacts and themotor for energizing the motor when the contact arm is in an unstableposition; a second contact arm frictionally engaging the rotary memberfor rotation therewith; a pair of resilient contacts connected with themotor, the frictional contact arm being mounted and positioned to engageone or the other of the resilient contacts in response to a rotation ofthe rotary member for controlling the direction of the motor rotation;and circuit means to cause the motor to rotate continuously by axiallymoving the rotary member whilemaintaim ing engagement of the firstcontact arm with one of the resilient contacts.

MICHEL N. YARDENY. CHARLES PRINDLE.

